<template>
  <div style="padding: 10px; margin-bottom: 50px">
    <el-row>
      <el-col :span="4">
        <el-card style="width: 300px; height: 300px; color: #333">
          <div style="padding-bottom: 10px; border-bottom: 1px solid #ccc">在线用户<span style="font-size: 12px">（点击聊天气泡开始聊天）</span></div>
          <div v-for="user in users" :key="user.username" style="padding: 10px 0">
            <span>{{ user.username }}</span>
            <i
              class="el-icon-chat-dot-round"
              style="margin-left: 10px; font-size: 16px; cursor: pointer"
              @click="chatUser = user.username"
            />
            <span v-if="user.username === chatUser" style="font-size: 12px;color: limegreen; margin-left: 5px">chatting...</span>
          </div>
        </el-card>
      </el-col>
      <el-col :span="20">
        <div
          style="width: 800px; margin: 0 auto; background-color: white;
                    border-radius: 5px; box-shadow: 0 0 10px #ccc"
        >
          <div style="text-align: center; line-height: 50px;">
            Web聊天室（{{ chatUser }}）
          </div>
          <div style="height: 350px; overflow:auto; border-top: 1px solid #ccc" v-html="content" />
          <div style="height: 200px">
            <textarea
              v-model="text"
              style="height: 160px; width: 100%; padding: 20px; border: none; border-top: 1px solid #ccc;
             border-bottom: 1px solid #ccc; outline: none"
            />
            <div style="text-align: right; padding-right: 10px">
              <el-button type="primary" size="mini" @click="send">发送</el-button>
            </div>
          </div>
        </div>
      </el-col>
    </el-row>
  </div>
</template>
<script>
import store from '@/store'
let socket
export default {
  name: 'Im',
  data() {
    return {
      circleUrl: 'https://cube.elemecdn.com/3/7c/3ea6beec64369c2642b92c6726f1epng.png',
      user: {},
      isCollapse: false,
      users: [],
      chatUser: '',
      text: '',
      messages: [],
      content: '',
      userInfo: {}
    }
  },
  created() {
    this.init()
  },
  methods: {
    send() {
      if (!this.chatUser) {
        this.$message({ type: 'warning', message: '请选择聊天对象' })
        return
      }
      if (!this.text) {
        this.$message({ type: 'warning', message: '请输入内容' })
      } else {
        if (typeof (WebSocket) === 'undefined') {
          console.log('您的浏览器不支持WebSocket')
        } else {
          console.log('您的浏览器支持WebSocket')
          // 组装待发送的消息 json
          // {"from": "zhang", "to": "admin", "text": "聊天文本"}
          const message = { from: this.userInfo.username, to: this.chatUser, text: this.text }
          socket.send(JSON.stringify(message)) // 将组装好的json发送给服务端，由服务端进行转发
          this.messages.push({ user: this.userInfo.username, text: this.text })
          // 构建消息内容，本人消息
          this.createContent(null, this.userInfo.username, this.text)
          this.text = ''
        }
      }
    },
    createContent(remoteUser, nowUser, text) { // 这个方法是用来将 json的聊天消息数据转换成 html的。
      let html
      // 当前用户消息
      if (nowUser) { // nowUser 表示是否显示当前用户发送的聊天消息，绿色气泡
        html = '<div class="el-row" style="padding: 5px 0">\n' +
          '  <div class="el-col el-col-22" style="text-align: right; padding-right: 10px">\n' +
          '    <div class="tip left">' + text + '</div>\n' +
          '  </div>\n' +
          '  <div class="el-col el-col-2">\n' +
          '  <span class="el-avatar el-avatar--circle" style="height: 40px; width: 40px; line-height: 40px;">\n' +
          '    <img src="https://cube.elemecdn.com/3/7c/3ea6beec64369c2642b92c6726f1epng.png" style="object-fit: cover;">\n' +
          '  </span>\n' +
          '  </div>\n' +
          '</div>'
      } else if (remoteUser) { // remoteUser表示远程用户聊天消息，蓝色的气泡
        html = '<div class="el-row" style="padding: 5px 0">\n' +
          '  <div class="el-col el-col-2" style="text-align: right">\n' +
          '  <span class="el-avatar el-avatar--circle" style="height: 40px; width: 40px; line-height: 40px;">\n' +
          '    <img src="https://cube.elemecdn.com/3/7c/3ea6beec64369c2642b92c6726f1epng.png" style="object-fit: cover;">\n' +
          '  </span>\n' +
          '  </div>\n' +
          '  <div class="el-col el-col-22" style="text-align: left; padding-left: 10px">\n' +
          '    <div class="tip right">' + text + '</div>\n' +
          '  </div>\n' +
          '</div>'
      }
      console.log(html)
      this.content += html
    },
    init() {
      this.userInfo.username = this.$store.state.user.username
      const username = this.userInfo.username
      console.log(this.userInfo.username)
      /* this.user = sessionStorage.getItem('user') ? JSON.parse(sessionStorage.getItem('user')) : {}
      const username = this.user.username*/
      const _this = this
      if (typeof (WebSocket) === 'undefined') {
        console.log('您的浏览器不支持WebSocket')
      } else {
        console.log('您的浏览器支持WebSocket')
        const socketUrl = 'ws://localhost:8080/imserver/' + username
        if (socket != null) {
          socket.close()
          socket = null
        }
        // 开启一个websocket服务
        socket = new WebSocket(socketUrl)
        // 打开事件
        socket.onopen = function() {
          console.log('websocket已打开')
        }
        //  浏览器端收消息，获得从服务端发送过来的文本消息
        socket.onmessage = function(msg) {
          console.log('收到数据====' + msg.data)
          const data = JSON.parse(msg.data) // 对收到的json数据进行解析， 类似这样的： {"users": [{"username": "zhang"},{ "username": "admin"}]}
          if (data.users) { // 获取在线人员信息
            _this.users = data.users.filter(user => user.username !== username) // 获取当前连接的所有用户信息，并且排除自身，自己不会出现在自己的聊天列表里
          } else {
            // 如果服务器端发送过来的json数据 不包含 users 这个key，那么发送过来的就是聊天文本json数据
            //  // {"from": "zhang", "text": "hello"}
            if (data.from === _this.chatUser) {
              _this.messages.push(data)
              // 构建消息内容
              _this.createContent(data.from, null, data.text)
            }
          }
        }
        // 关闭事件
        socket.onclose = function() {
          console.log('websocket已关闭')
        }
        // 发生了错误事件
        socket.onerror = function() {
          console.log('websocket发生了错误')
        }
      }
    }
  }
}
</script>
<style>
.tip {
  color: white;
  text-align: center;
  border-radius: 10px;
  font-family: sans-serif;
  padding: 10px;
  width:auto;
  display:inline-block !important;
  display:inline;
}
.right {
  background-color: deepskyblue;
}
.left {
  background-color: forestgreen;
}
</style>
